In machines where a series or sequence of operations is to be performed, such as, for example, the movement of a spindle, the opening and closing of a fixture, the starting and stopping of a clutch and brake system, etc., it has been necessary heretofore, to provide a multiplicity of electrical circuits for each operation, plus interlocking circuitry, limit switches, etc. Each circuit was to actuate a solenoid for operating a valve to provide fluid pressure to perform a function. Not only did this require an excessive amount of wiring, but also, when a malfunction occurred in the machine, it was difficult and time-consuming to trace the circuitry, and eventually determine the cause, and to remedy it.
The present invention overcomes all of these problems by eliminating most of the electrical circuitry, and wiring, and by providing a positve mechanical lock-in for each operation for safety, rather than interlocking electrical circuitry, and a simple and quick method of programming a sequence of operations.